Color Tunable Medical Headlamp Bezel

ABSTRACT

A color-adjustable medical headlamp assembly, including a headband assembly and a bezel, which can be worn around a user&#39;s head. The bezel contains a light source assembly that is capable of generating light with different colors and intensities, and an optical train that focuses the light generated by the light source assembly. A user input assembly is included to allow for the selection and adjustment of both the color and brightness of the light from the bezel. Also, the rear surface of the bezel has a higher coefficient of thermal conductance compared to the movable portion of the bezel and is an avenue for heat dissipation. Finally, a heat shield is attached to the bezel to cover its rear surface, which can pose a burn hazard after prolonged usage.

RELATED APPLICATIONS

This application is a continuation of application U.S. Ser. No.15/892,768, filed Feb. 9, 2018, now U.S. Pat. No. 10,708,990, issuingJul. 7, 2020, which is incorporated by reference as if fully set forthherein.

BACKGROUND

Medical lighting of different colors can provide various benefits.Distinguishing various tissue types, assisting a color-blind surgeon orsimple personal preference may cause a color blend that is optimal for afirst surgeon, in a first situation, is not optimal for a second surgeonin a second situation.

Another problem in the design of medical headlamp assemblies is that ofexhausting heat from the bezel (also referred to as “headlamp”). Atypical bezel is only about the size of an acorn, with limited surfaceto radiate heat. If the surface area becomes too hot, it creates a burnhazard. While LEDs do not heat up as much as other conventional lightsources, the use of an LED assembly would still cause the temperature ofsurrounding areas within the bezel to increase, especially duringmedical operations that span hours.

SUMMARY

The following embodiments and aspects thereof are described andillustrated in conjunction with systems, tools and methods which aremeant to be exemplary and illustrative, not limiting in scope. Invarious embodiments, one or more of the above-described problems havebeen reduced or eliminated, while other embodiments are directed toother improvements.

In a first aspect, the present invention relates to a medical headlampassembly, comprising a headband assembly adapted to fit around a user'shead, and a bezel that is connected to and supported by a linkage to theheadband assembly. The bezel includes a light source assembly that iscapable of producing light of differing colors and intensities, and anoptical train that focuses the light generated by the light sourceassembly. A user input assembly is also included to permit user controlover the color and intensity from the bezel.

In a second aspect, the present invention relates to a medical headlampassembly, comprising a headband assembly adapted to fit around a user'shead, and a bezel connected to and supported by a linkage to theheadband assembly. The bezel includes a housing that comprises astationary portion and a moveable portion, where the moveable portionacts to adjust some element of the bezel and has an exterior surface.The bezel further includes a light source assembly to generate a lightbeam, and an optical train for focusing the light beam from the bezel,both of which are held within the housing. The rear surface of thebezel, which is part of the stationary portion, has a higher coefficientof thermal conductance than the exterior surface of the moveableportion; the rear surface of the bezel heats up more readily compared tothe exterior surface of the moveable portion and provides an avenue forheat dissipation. Lastly, a heat shield is attached to the bezel andcovers the rear surface of the bezel to protect a user from possibleburns.

In addition to the exemplary aspects and embodiments described above,further aspects and embodiments will become apparent by reference to thedrawings and by study of the following detailed descriptions.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are illustrated in referenced drawings. It isintended that the embodiments and figures disclosed herein are to beconsidered illustrative rather than restrictive.

FIG. 1 is an isometric detail view of the bezel and headband connectionarea, of the headlamp assembly of FIG. 1.

FIG. 2 shows a sectional view of the bezel of FIG. 1.

FIG. 3 is an isometric view of the heat shield.

FIG. 4 is a side view of the bezel of FIG. 1, with the heat shieldattached, and shown in a sectional view

FIG. 5 is a block diagram of the electronics of the medical headlampassembly of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In a preferred embodiment of a medical headlamp assembly 10, accordingto the present invention, a headband assembly 12 supports bezel 16 (FIG.1). The medical headlamp assembly 10 includes a headband 18, a bezel 16,and a heat shield 20 positioned at the back of, and attached to, thebezel 16, as is described further below in reference to FIG. 4. Bezel 16is attached to headband 18 via linkage 22.

Referring to FIGS. 1 and 2, a bezel 16 is connected to the headbandassembly 18 through linkage 22. The bezel 16 includes a housing 24,which comprises a stationary portion 26, and a moveable portion in theform of an outer ring 28. The stationary portion 26 houses a piece ofcircuit 30 with conductive traces (not shown) that are adapted to powera light source assembly 32, which is described below. The stationaryportion 26 defines a channel 34, which allows for the insertion of afirst end of cable 36 to supply electricity to the conductive traces. Ina preferred embodiment, the second end of cable 36 is a USB connector80, which can be inserted into USP port 82 and establish electricalconnection between light source assembly 32 and circuit board 84.Circuit board 84 is included to permit color and intensity control overlight source assembly 32, which will be described in greater detailbelow.

Again, referring to FIG. 2, light source assembly 32 is positioned atthe back of and extends into the interior cavity of stationary portion26. An optical train 38 is positioned in front of light source assembly32. The optical train 38 includes a series of fly-eye lens arrays 40,and an exit lens 42 that is held by an exit lens holder 44, which inturn is surrounded and held by outer ring 28. During operation, thelight generated by light source assembly 32 passes through optical train38 to produce a light beam with a substantially homogenous intensity.

In preferred embodiments, the size of the light beam is adjustable asrequired for various applications. As illustrated in FIG. 2, the opticaltrain 38 can further include an iris 46 adjustable by actuator 48,positioned between the fly-eye lens arrays 40 and the exit lens 42,which focuses the light beam generated by light source assembly 32. Thebeam radius can be further tuned by changing the position of the exitlens 42 within housing 24. In preferred embodiments, adjustment of theiris 46 by actuator 48 and the positioning of exit lens 42 withinhousing 24 are both coupled to the rotational motion of outer ring 28,such that the beam size is adjusted when the user rotates outer ring 28.In an alternative preferred embodiment, iris 46 is not present, and thebeamwidth is adjusted solely by focusing (moving) the exit lens 42.

Referring to FIG. 5, batteries 60 (typically attached to headbandassembly 12) power a microcontroller 62 (located on circuit board 84(shown in FIG. 1)), which receives input from a user input device 64,commanding color and brightness. In response microcontroller 62 controlsLED drivers 66, 68 and 70 (also located on circuit board 84), whichpower LEDs 72, 74 and 76, respectively, in light source assembly 32(FIG. 2). LED drivers 66, 68 and 70 are, in one embodiment, DC-to-DCconverters, but could also be pulse width modulated drivers or someother type of device that has a controllable, variable power output. Inembodiments, a fourth LED is added, producing amber, or white, light.

The three LEDs, 72, 74 and 76, chosen so that varying the light outputof the LEDs 72, 74 and 76, can produced any color of visible light.Also, a broad range of spectra may be produced, by varying the power tothe three LEDS 72, 74 and 76. In one embodiment, the three LEDs colorsare red, green and blue, but in another preferred embodiment, the threeLED colors are cyan, purple and yellow. In another embodiment, two LEDsare chosen to be at the extremes of the visible light spectrum, red andviolet, with the third in the middle (green or cyan). The LEDs arecontrolled to produce a broad choice of beam spectra, to achieve notonly a certain beam color, but also different reflectivecharacteristics. Although two beams may appear to be exactly the same toa human observer, because each one stimulates the retinal cones equally,the reflections from tissue of the two beams may be different, if aspectrum has less light of a frequency that reflects from a particulartype of tissue. By careful selection of a spectrum, it is possible toprovide a greater degree of color contrast between different types oftissue.

For example, the beam spectrum can be selected such that when used toilluminate a biological structure, the light beam causes one tissue typeto contrast with a second tissue type (i.e. enhancing the colordifference between healthy tissue and focal tissues upon illumination,optimally illuminating various tissue types such as skin, muscle, fat,blood vessels, and organs). In the case in which the LED assemblycomprises a red LED, a green LED, and a violet LED, the red and theviolet LEDS may be illuminated at maximum power, and the green LED notused, to accentuate color contrast between different types of tissue,having different reflective characteristics, with one tissue type beingmore reflective of low frequency light (red tissue) and other tissuebeing more reflective of high frequency light (bone, which appears tohave more reflectance across the spectrum). As another example, thecolors of the LEDs can be selected such that light source assembly 32emits light with a lower intensity within the range of 500 nm-590 nm, asopposed to light within the range of 420 nm-470 nm or in the range590-700 nm; a beam having this spectral profile would be suitable forusers with deuteranopia (red-green color blindness), as they have areduced ability to see light in the 470 to 590 nm range. In oneembodiment a spectrum is chosen to highlight a dye injected to show aparticular feature or diseased portion of an organ. In embodiments, anultraviolet or infrared LED is included in assembly 32, to causefluorescence of a dye, or some other effect. The use of agents can beused to identify diseased tissue and may also be used to identifylocations of hemorrhage during surgery. In embodiments, differentspectra are interleaved over time, so that a surgeon can periodicallyobtain a view highlighting a dye or other sort of agent, and then resumea view illuminated, for example, by white light. In one embodiment,white light illumination is interrupted every minute, for five seconds,by a beam spectrum designed to highlight a particular type of tissue orparticular dye that has been previously injected. In another embodiment,white light illumination is interrupted every three minutes, for fiveseconds with special-purpose spectrum.

In preferred embodiments of the present invention, both the color andthe brightness of the light beam are adjustable through a user inputassembly 64. In some embodiments, the user input assembly 64 forms partof headband 18 and is electrically coupled to the microcontroller 62,which is physically located on circuit board 84. In one such embodiment,the user input assembly 64 includes control knobs (not shown) that arecoupled to the microcontroller 62. For instance, a brightness controlknob can be used to simultaneously adjust the brightness of the LEDs 72,74 and 76, thereby controlling the overall intensity of the light beamfrom the bezel 16, while a color control knob is used to vary the colorof the light beam, by changing the proportion of light produced by eachLED 72, 74 and 76. In an alternative embodiment, a separate powercontrol knob is provided for each LED 72, 74 and 76.

In one embodiment, the user input assembly 64 additionally includesuser-preset color spectra, that are configured to provide contrastbetween certain tissue types, or to highlight a particular tissue type,such as bone. In embodiments, a set of buttons (not shown) are providedon the headstrap, each one activating a different preset color spectrum.In certain embodiments, the preset color spectra can be customized. Forexample, each preset spectrum button can be configured so that if it isheld down for an extended period (for example, 2 seconds), the presetspectra that is selected by that button can then be set by whateversystem is made available for adjusting the light beam spectrum, forexample a set of knobs. After adjusting the knob(s) until a desiredspectrum is achieved, another extended-period press of that button wouldenter that spectrum into memory (of microcontroller 62), so that it canbe reselected at the push of that button. In one embodiment, somebuttons are provided that are not pre-loaded with a preset spectrum, topermit the user to add preset spectra of his choosing, without erasing afactory-set spectrum.

In alternative embodiments, the user input assembly 64 is installed ontoan electronic platform, such as a computer (tablet, laptop or desktop)or a smartphone, and is in wireless communication with themicrocontroller 62 on circuit board 84, using a wireless protocol suchas Wi-Fi or Bluetooth. A graphical user interface (not shown) permitsadjustment of color and brightness of the light beam. This interfacecan, for example, display a color triangle containing all possible beamcolors as determined by the power delivered to each LED 72, 74 and 76wherein the beam color is selected by the user simply by clicking on, orin the case of a touch-screen, touching, the desired option shown withinthe color triangle. Alternatively (or concurrently), the graphical userinterface can offer the option of manually inserting intensity values(ranging from 0-100%, for example) for the individual LEDs, which canallow for fine control over the resulting color of the light beam. Thebrightness is adjusted by using a brightness slider, whichsimultaneously increases or decreases the intensities of all LEDs. Thegraphical user interface can additionally include the option to selectand save user-customizable, preset color spectra as described earlier.To anticipate the situation involving multiple users, the preset colorspectra is configured to correspond to individual bezels, and/or tospecific LED color combinations, which would change the beam coloroptions. In additional embodiments, the user input assembly 64 includesa voice command device, which permits voice control over the lightsource assembly 32 through the electronic platform.

While an LED assembly offers flexibility in beam color selection, it maybe necessary to swap out the bezel 16 should the medical headbandassembly of the present invention be used by multiple users, who mayrequire different beam colors and preset color spectra as dictated byspecific tasks, the users' preferences, or their needs. A change inbezel 16 would also be needed if it is damaged, especially during amedical operation. Referring back to FIG. 1, bezel 16 is attached toheadband 18 through linkage 22. In preferred embodiments, bezel 16 andlinkage 22 can be detached from headband 18 and thereby forming aremovable sub-assembly 14 of medical headlamp assembly 10, providing theease of bezel replacement.

In preferred embodiments, the stationary portion 26 of the housing isconstructed from a light-weight metal. Examples of suitable light-weightmetals include aluminum, and alloys of aluminum. During operation ofmedical headlamp assembly 10, heat is generated by light source assembly32, which is conducted throughout the body and external surface of thebezel 16. As a result, the metallic portions of the bezel 16 pose a burnhazard, especially during extended periods of usage. In order to reducethe risk of burns from touching the surface of the bezel 16 duringoperation, portions of the bezel 16 can be coated with a material thathas a lower coefficient of thermal conduction than the surface of thebezel 16. In a preferred embodiment, a coating is applied to outer ring28. The coating material is selected from a number of heat-insulatingmaterials, such as, but not limited to ceramics, polymers, silicones,and mixtures thereof. In preferred embodiments, the coating is aceramic. In certain embodiments, the ceramic coating is a coatingconstructed of aluminum oxide, zirconium oxide, or mullite. In otherembodiments, the coating is a ceramic coating available from Cerakote®.It is to be appreciated that the coating can be applied to additionalareas that will be touched by the user, and thus can be applied to anyportion of the exterior surface of the bezel 16 as deemed necessary. Inpreferred embodiments, the thickness of the coating is less than 0.1 mm.In an alternate embodiment, the outer ring 28 is constructed of amaterial having a lower coefficient of thermal conductance than thematerial used to construct stationary portion 26.

As overheating of the interior of bezel 16 and light source assembly 32is undesirable due to negative effects on device performance andlifetime (i.e. reduction in light output, loss in efficiency,degradation of the LED junction element), effective heat dissipation isnecessary. In preferred embodiments of the present invention, the lightsource assembly 32 is situated against the rear of the interior ofstationary portion 26. Due to the proximity to the light source assembly32, which generates heat during operation of the device, the rear end ofbezel 16 would necessarily heat up at a higher rate compared to portionsof bezel 16 that are further removed from light source assembly 32.Hence, the surface of this rear end presents an avenue for heatdissipation, especially in embodiments where portions of the externalsurface of bezel 16 is coated with a heat-insulating material, asdescribed above, which hinders heat dissipation through these portions.In order to simultaneously allow for heat dissipation through the rearsurface of bezel 16 and also protect the user from possible burns fromtouching said surface, a heat shield 20 is attached to bezel 16, asillustrated in FIGS. 1, 2, and 4.

Referring to FIGS. 3 and 4, heat shield 20 comprises a panel 50 thatdefines apertures 52 to allow heat to flow from the rear surface ofbezel 16 through heat shield 20. Heat shield 20 further comprises a sideportion 54, which extends from the outer edge of panel 50 in thedirection substantially perpendicular to the plane defined by panel 50towards bezel 16 and covers the rear portion of bezel 16. In preferredembodiments, side portion 54 extends upward beyond panel 50 and defineholes 56, with which heat shield 20 is attached to bezel 16 by couplingto protrusions 58 on bezel 16, having shapes that are complimentary toholes 56. In preferred embodiments, heat shield 20 can be detached frombezel 16 by disengaging holes 56 from protrusions 58. In a preferredembodiment, holes 56 and protrusions 58 are circular in shape, such thatheat shield 20, when attached to bezel 16, is moveable and can berepositioned to expose the rear surface of bezel 16.

As heat radiates from the rear surface of bezel 16 and passes throughapertures 52, heat shield 20 can also heat up and present a burn hazard,depending on the material used for its construction. Therefore, the heatshield 20 is ideally constructed of a material that is a thermalinsulator, such as plastic. Alternatively, the surface of the heatshield 20 is coated with a material having a lower coefficient ofthermal conductance than the material used to construct heat shield 20.Non-limiting examples of suitable coating materials include ceramics,polymers, silicones, and mixtures thereof. The coating material isselected from a number of heat-insulating materials, such as, but notlimited to ceramics, polymers, silicones, and mixtures thereof. Inpreferred embodiments, the coating is a ceramic. In certain embodiments,the ceramic coating is a coating constructed of aluminum oxide,zirconium oxide, or mullite. In other embodiments, the coating is aceramic coating available from Cerakote®. In a preferred embodiment, thethickness of the coating is less than 0.1 mm. As will be appreciated bya person skilled in the art, the appropriate thickness of the coatingwill depend on the properties of the coating material.

While a number of exemplary aspects and embodiments have been discussedabove, those possessed of skill in the art will recognize certainmodifications, permutations, additions and sub-combinations thereof. Itis therefore intended that the following appended claims and claimshereafter introduced are interpreted to include all such modifications,permutations, additions and sub-combinations as are within their truespirit and scope.

1. A medical headlamp assembly, comprising: (a) a headband assembly; (b)a bezel connected to and supported by a linkage to said headbandassembly, including: (i) a light source assembly capable of producinglight of differing colors and differing intensities; (ii) an opticaltrain for focusing said light from said light source assembly; (c) auser input assembly, permitting a user to adjust the color and intensityof light from said bezel.
 2. The medical headlamp assembly of claim 1,wherein said light source assembly is an LED assembly.
 3. The medicalheadlamp assembly of claim 1, wherein said light source assembly is anLED assembly that includes at least three LEDs, each of a differentcolor.
 4. The medical headlamp assembly of claim 1, wherein said lightsource assembly is an LED assembly that includes a red LED, a green LED,and a blue LED.
 5. The medical headlamp assembly of claim 1, whereinsaid user input assembly permits the choice of preset color spectra,adapted for specific tasks.
 6. The medical headlamp assembly of claim 5,wherein one preset color spectrum emits less light between 500 nm to 550nm, in comparison with light between 420 nm and 470 nm.
 7. The medicalheadlamp assembly of claim 5, wherein at least one preset color spectrumcauses a first tissue type to contrast with a second tissue type.
 8. Themedical headlamp assembly of claim 1, including an ultraviolet LED. 9.The medical headlamp assembly of claim 1, including an infrared LED.